Enable to show a bit of subtlety (3)
I believe the answer is:
let
'enable' is the definition.
(I've seen this in another clue)
'a bit of subtlety' is the wordplay.
'a bit of' says the answer is hidden in the clue.
'LET' is hidden within 'subtlety'.
'to show' is the link.
(Other definitions for let that I've seen before include "Permit; lease" , "Allow on the tennis court" , "Disappoint or fail to support - ... down" , "Allow, don't hinder" , "Rent out (property)" .)